vendor/llvm/llvm-trunk-r338150

1 files changed, 36 insertions, 14 deletions

diff --git a/lib/Support/SmallVector.cpp b/lib/Support/SmallVector.cpp
index 74313151c762..1070c6672edc 100644
--- a/lib/Support/SmallVector.cpp
+++ b/lib/Support/SmallVector.cpp
@@ -14,31 +14,53 @@
 #include "llvm/ADT/SmallVector.h"
 using namespace llvm;
 
+// Check that no bytes are wasted and everything is well-aligned.
+namespace {
+struct Struct16B {
+  alignas(16) void *X;
+};
+struct Struct32B {
+  alignas(32) void *X;
+};
+}
+static_assert(sizeof(SmallVector<void *, 0>) ==
+                  sizeof(unsigned) * 2 + sizeof(void *),
+              "wasted space in SmallVector size 0");
+static_assert(alignof(SmallVector<Struct16B, 0>) >= alignof(Struct16B),
+              "wrong alignment for 16-byte aligned T");
+static_assert(alignof(SmallVector<Struct32B, 0>) >= alignof(Struct32B),
+              "wrong alignment for 32-byte aligned T");
+static_assert(sizeof(SmallVector<Struct16B, 0>) >= alignof(Struct16B),
+              "missing padding for 16-byte aligned T");
+static_assert(sizeof(SmallVector<Struct32B, 0>) >= alignof(Struct32B),
+              "missing padding for 32-byte aligned T");
+static_assert(sizeof(SmallVector<void *, 1>) ==
+                  sizeof(unsigned) * 2 + sizeof(void *) * 2,
+              "wasted space in SmallVector size 1");
+
 /// grow_pod - This is an implementation of the grow() method which only works
 /// on POD-like datatypes and is out of line to reduce code duplication.
-void SmallVectorBase::grow_pod(void *FirstEl, size_t MinSizeInBytes,
+void SmallVectorBase::grow_pod(void *FirstEl, size_t MinCapacity,
                                size_t TSize) {
-  size_t CurSizeBytes = size_in_bytes();
-  size_t NewCapacityInBytes = 2 * capacity_in_bytes() + TSize; // Always grow.
-  if (NewCapacityInBytes < MinSizeInBytes)
-    NewCapacityInBytes = MinSizeInBytes;
+  // Ensure we can fit the new capacity in 32 bits.
+  if (MinCapacity > UINT32_MAX)
+    report_bad_alloc_error("SmallVector capacity overflow during allocation");
+
+  size_t NewCapacity = 2 * capacity() + 1; // Always grow.
+  NewCapacity =
+      std::min(std::max(NewCapacity, MinCapacity), size_t(UINT32_MAX));
 
   void *NewElts;
   if (BeginX == FirstEl) {
-    NewElts = malloc(NewCapacityInBytes);
-    if (NewElts == nullptr)
-      report_bad_alloc_error("Allocation of SmallVector element failed.");
+    NewElts = safe_malloc(NewCapacity * TSize);
 
     // Copy the elements over.  No need to run dtors on PODs.
-    memcpy(NewElts, this->BeginX, CurSizeBytes);
+    memcpy(NewElts, this->BeginX, size() * TSize);
   } else {
     // If this wasn't grown from the inline copy, grow the allocated space.
-    NewElts = realloc(this->BeginX, NewCapacityInBytes);
-    if (NewElts == nullptr)
-      report_bad_alloc_error("Reallocation of SmallVector element failed.");
+    NewElts = safe_realloc(this->BeginX, NewCapacity * TSize);
   }
 
-  this->EndX = (char*)NewElts+CurSizeBytes;
   this->BeginX = NewElts;
-  this->CapacityX = (char*)this->BeginX + NewCapacityInBytes;
+  this->Capacity = NewCapacity;
 }